1. Field of the Invention
The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and an apparatus for beam allocation in a wireless communication system.
2. Description of the Related Art
Wireless communication systems are advancing to support a high data rate and keep up with the continuously increasing demand for wireless data traffic.
Up to now, 4th Generation (4G) systems mainly aim to improve spectral efficiency in order to increase a data transfer rate. However, it is hard to satisfy the continuously increasing demand for wireless data traffic merely with the spectral efficiency enhancement.
To address this issue, one method utilizes a wide frequency band. Since it is difficult to ensure the wide frequency band in the current frequency (i.e., below 10 GHz), a wider frequency band is needed.
However, as the transmission frequency for the wireless communication rises, a propagation distance is relatively shortened, thereby reducing the service coverage area. One way of addressing this issue is by implementing a beamforming technique which expands the propagation distance.
The transmit beamforming can expand a signal transmission distance and concentrates the propagation region in a specific direction using a plurality of antennas. The group of the antennas is referred to as an antenna array, and the antenna in the antenna array is referred to as an array element. Since signals are rarely transmitted in directions other than the corresponding direction, interference on other user signals can be greatly mitigated.
A receiver can carry out the receive beamforming using a receive antenna array. The receive beamforming also concentrates the propagation reception in a particular direction, thereby increasing a gain of the signal received in the corresponding direction, and excludes signals received in directions other than the corresponding direction, from the received signal which blocks interference signals.
The beamforming uses a technique for measuring/selecting transmit (Tx) and receive (Rx) beams and for feeding back the selected beam information in a base station and a mobile station. When feeding back the beam information, the base station and the mobile station can transmit information of one or more optimal beams for the sake of beam diversity and beam scheduling flexibility. In so doing, when allocating data and control resource, the base station can allocate the beam by selecting all or part of the multiple beams. Hence, for the transmit and receive beamforming of the mobile station and the base station, the base station needs to specifically provide the beam allocation information to the mobile station, or a definite beam allocation method needs to be defined in advance when the data and the control resource are allocated.
Therefore, a need exists for a method and an apparatus for efficiently allocating a Tx beam in a wireless communication system.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.